1. Technical Field
The present invention relates to low calorie fat compositions. More specifically, the present invention relates to triglyceride compositions containing acylated glycerides for use in low calorie fat compositions, and in particular, the use of such triglyceride compositions in low calorie fat-containing food compositions.
2. Background
One of the most common metabolic conditions today is obesity. Of the various reasons for the condition, ingestion of a greater number of calories than are needed is a primary factor. The typical diet comprises about 40% of the total calories from fat, however, dietary guidelines call for reducing fat intake to less than 30% of the total calorie intake.
Fat contributes much to the palatability and flavor of food as most flavor compounds are fat soluble. Furthermore, fats contribute to the satiety value of foods since fatty foods are slower to digest than foods containing protein and carbohydrates. In addition, fats are carriers of fat soluble vitamins, such as A, D, E, and K, and essential fatty acids, which have been shown to be important in growth and maintenance of many body functions.
One of the major problems with dietary fats is that it is highly calorically dense, about 9 calories per gram, compared to about 4 calories per gram for proteins and carbohydrates. Furthermore, dietary fats can be readily stored by the body when consumed in excess, contributing to the obesity condition. Hence, major research efforts have focused on ways to produce food substances that provide the same functionality and organoleptic properties as fats, but with fewer calories. Recently, research efforts have focused on the synthesis of low calorie fats (U.S. Pat. No.3,579,548; Hamm, (1984) J. Food Sci. 49:419-428; EP 0910955; U.S. Pat. No.3,637,774, and U.S. Pat. No.4,582,715), and several products are currently on the market. Synthetic fats have been created and are currently being marketed. Unfortunately, many consumers are concerned with the gastrointestinal side effects associated with the synthetic fats, as well as with vitamin sequestration.
There is a need in the art for low calorie fat compounds which have the preferable organoleptic properties of normal triglyceride fats, are readily attainable or produced, and do not have adverse side effects.
By this invention, low calorie triglyceride compositions and food compositions incorporating them are provided. The triglyceride compositions described herein provide a reduced caloric value compared to normal triglyceride containing fats and oils. In addition, the triglyceride compositions of the present invention have the preferable organoleptic properties of normal triglycerides.
Thus, a first aspect of the present invention provides low calorie fat compositions comprising acylated glycerides. The acylated glyceride compositions of the present invention find particular use in the preparation of various food compositions as a low calorie fat.
Another aspect of the present invention provides a low calorie triglyceride composition containing at least one acylated hydroxy fatty acid having desirable organoleptic properties and functional characteristics useful in a wide variety of food applications. Furthermore, the low calorie triglycerides of the present invention are hydrolyzed by pancreatic lipases similarly to normal triglycerides, however, the resulting hydrolyzed hydroxy fatty acids are poorly absorbed in the intestines.
The acylated hydroxy fatty acid for use in the acylated glyceride compositions of the present invention have a melting temperature above about 40xc2x0 C., preferably, the acylated hydroxy fatty acids have a melting temperature between about 40xc2x0 C. and about 120xc2x0 C., more preferably between about 50xc2x0 C. and about 115 xc2x0 C, most preferably between about 60xc2x0 C. to about 110xc2x0 C.
The acylated hydroxy fatty acids for use in the low calorie triglyceride compositions can be either saturated or unsaturated. Preferably the saturated acylated hydroxy fatty acids can be short, medium or long chain fatty acids, and the unsaturated acylated hydroxy fatty acids are long chain fatty acids. The other positions of the triglyceride molecule are occupied by aliphatic groups, hydrogen, or additional acylated hydroxy fatty acids.
In another aspect of the present invention, low calorie fat compositions of particular interest in the present invention comprise a triglyceride having the formula: 
where at least one of the X, Y and Z groups is an acylated hydroxy fatty acids having the formula (II) or (III): 
wherein a is 0 to 24, b is 5 to 24 and c is 0 to 22, and R1 and R2 are hydrogen or structure IV. 
where d is 0 to 24. The remainder of X, Y, and Z comprise short chain fatty acids (C2 to C5) or medium chain fatty acids (C6 to C12), long chain fatty acids (C13 to C26), additional acylated hydroxy fatty acids of formulas II, III and IV or hydrogen.
The acylated glycerides can be used either alone or in combination with additional vegetable oils. Furthermore, the compositions can be hydrolyzed to the high melting and poorly absorbed long chain acylated hydroxy fatty acids.
The acylated glycerides of the present invention particularly find use in low calorie food compositions.
In accordance with the subject invention, compositions and methods related to triglycerides are provided. In particular, the present invention provides acylated glyceride compositions and methods of use.
The present invention relates to acylated glycerides having the formula (I): 
where at least one of the X, Y and Z groups is an acylated fatty acid having the formula (II) or (III): 
wherein a is 0 to 24, b is 5 to 24 and c is 0 to 22, and R1 and R2 are hydrogen or structure IV. 
where d is 0 to 24. The remainder of X, Y, and Z comprise short chain fatty acids (C2 to C5) or medium chain fatty acids (C6 to C12), long chain fatty acids (C13 to C26), additional acylated hydroxy fatty acids of formulas II, III and IV or hydrogen.
The acylated glycerides of the present invention find use in the preparation of low-fat containing food compositions, which comprise non-fat and fat ingredients, where about 10% to about 100% by weight of the fat ingredients comprise the acylated glycerides of the present invention.
The acylated glycerides of the present invention, and fat-containing food compositions containing these compounds, have desirable physical properties and palatability compared to ordinary triglyceride fats and compositions containing same. However, these triglycerides have substantially lower effective caloric value because even though they can be readily hydrolyzable by lipase, they are poorly absorbed in the intestinal tract and are thus reduced in caloric availability compared to ordinary triglyceride fat. The acylated glycerides and the food compositions containing these compounds which are low in available calories are referred to herein as xe2x80x9clow caloriexe2x80x9d.
The acylated glycerides of particular interest in the present invention comprise a glycerol backbone, esterified to at least one acylated hydroxy fatty acid at the sn-1, sn-2, and/or sn-3 positions of the triglyceride. The remainder of the positions of the glycerol molecule are occupied by aliphatic groups, straight chain or branched, including substituted, hydrogen, or additional acylated hydroxy fatty acids.
Thus, a first aspect of the present invention provides triglyceride compositions comprising at least one acylated hydroxy fatty acid. Such compositions are referred to herein as acylated glycerides.
Another aspect of the present invention provides a triglyceride composition having the formula: 
where at least one of the X, Y and Z groups is an acylated hydroxy fatty acids having the formula (II) or (III): 
wherein a is 0 to 24, b is 5 to 24 and c is 0 to 22, and R1 and R2 are hydrogen or structure IV. 
where d is 0 to 24. The remainder of X, Y, and Z comprise short chain fatty acids (C2 to C5) or medium chain fatty acids (C6 to C12), long chain fatty acids (C13 to C26), additional acylated fatty acids of formulas II, III and IV or hydrogen.
Any acylated hydroxy fatty acid can be used in the low calorie fat triglycerides of the present invention. Preferred hydroxy fatty acids for use in the compositions of the present invention include those that have a melting temperature above about 40xc2x0 C. In particular, the estolide fatty acids have a melting temperature between about 40xc2x0 C. and about 120xc2x0 C., preferably between about 40xc2x0 C. and about 115xc2x0 C, more preferably, between about 50xc2x0 C. and about 110 xc2x0C.
Furthermore, the acylated glyceride compositions of the present invention can be made up of saturated or unsaturated acyl hydrocarbons and contain between about 1 and about 30 carbons. Particularly, saturated fatty acids contain between about 1 and about 30 carbons, more preferably between about 1 and about 26 carbons, most especially preferable between about 1 and about 22 carbons. Furthermore, the acylated hydroxy group can be substituted at any position of the fatty acid chain, and can include more than one estolide group along the fatty acid chain preferably the acylated group is internal or terminal on the hydroxy fatty acid, more preferably the acylated group is at carbon 6 or greater on the hydroxy fatty acid. Unsaturated fatty acids for use in the acylated hydroxy fatty acid triglyceride compositions of the present invention are preferably long chain unsaturated estolide fatty acids having at least about 18 carbons to about 30 carbons.
The acylated hydroxy fatty acids for use in the low calorie triglyceride compositions of the present invention can be natural or synthetic. Synthetic acylated hydroxy fatty acids can be produced using any method available to the skilled artisan. Natural acylated fatty acids can also be obtained from natural sources such as bacterial or plant sources.
Examples of hydroxy fatty acids for use in the preparation of the compositions of the present invention include, but not limited to, saturated natural estolide fatty acids juniperic acid, butolic acid, ipurolic acid, dihydroxy stearic acids, dihydroxy palmitic acids, hydroxynervonic acid, alpha-kamlolenic acid, beta-kamlolenic acid, or hydrogenated natural hydroxy acids ricinoleic, isoricinoleic, densipolic, lesquerolic, auricolic, ximenynolic, isanolic, dimorphecolic, coriolic, or synthetic saturated hydroxy faty acids 9-hydroxy stearic acid, 10-hydroxy stearic acid. The hydroxy acids also include saturated dihydroxy and polyhydroxy acids like ipurolic, ustilic, aleuritic, 12,13-dihydroxypalmitic and 12,13-dihydroxystearic, 9,10-dihydroxystearic acids.
Additional fatty acids for use in the acylated fatty acid triglyceride compositions of the present invention can be derived from straight chain fatty acids and/or branched chain fatty acids of chains 2 to 14 carbons long. The term fatty acids encompasses synthetic and natural organic carboxylic acids having the formula represented as RCOOH. Examples of this type of saturated fatty acids include, but are not limited to, acetic, propionic, butyric, caproic, caprylic, capric, lauric, myristic acids. The triglycerides derived from these compounds can have one to three of the acylated fatty acids. These triglycedies can be derived from random mixtures of acylated fatty acids and non-acylated fatty acids.
The acylated fatty acid triglyceride compositions of the present invention provide a triglyceride oil source having reduced caloric availability compared to normal triglyceride fats and oils. The estolide containing triglyceride compositions of the present invention preferably provide less than about 6.5 kcal/g, more preferably less than 6.0 kcal/g, especially preferred less than about 5.6 kcal/g. Caloric availability can be determined using a variety of methods such as those described, for example, by Finley, et al ((1994) J. Agric. Food Chem. 42:489-494) and Peters et al. (1993) J. Amer. College of Toxic. 10:357-367.
In addition, other analysis can be helpful in determination of digestibility and or absorbability of acylated fatty acid triglyceride compounds. For example, resistance to hydrolysis by pancreatic enzymes can determine the digestibility of the acylated fatty acid triglyceride molecules in vitro. Preferably, the acylated fatty acid triglyceride compositions of the present invention are readily hydrolyzed by pancreatic lipases, similar to normal corn triglycerides. As used herein, xe2x80x9chydrolyzed by pancreatic lipase similarly to normal corn oilxe2x80x9d refers to hydrolysis of the acylated fatty acid from the glycerol backbone by lipase at a rate at least about 60% of that of normal corn oil, preferably at a rate of at least about 70% of that of corn oil. Methods for in vitro pancreatic lipase analysis are known in the art and are described for example by Volpenhein (U.S. Pat. No. 4,582,715).
The acylated glyceride compositions for use as low calorie fat compositions of the present invention can be obtained from any source, including natural and synthetic sources. Also included as a source of the acylated glycerides are genetically engineered sources, such as yeasts, bacterial, plants and the like.
Acylated fatty acids for use in the triglyceride compositions of the present invention can be produced using any method available in the art from a wide variety of starting materials. For example, acylated fatty acids, or their esters, can be used as starting material for the production of the acylated fatty acid triglyceride compositions of the present invention. Alternatively, natural acylated fatty acid triglyceride sources can also be employed, or unsaturated fatty acids can be hydroxylated, or substituted fatty acids can also be used.
Thus, the acylated glyceride compositions of the present invention provide low calorie fat compositions which find use in the preparation of a wide variety of food applications.
The low calorie fat compositions of the present invention can be used as a partial or total replacement for normal fats in any fat-containing food product comprising fat and nonfat ingredients to provide reduced calorie benefits. In order to obtain a significant reduction in calories, at least about 5%, and preferably at least about 20%, of the total fat in the food product comprises the low calorie fat composition of the present invention. Alternatively, 100% replacement of normal fats with the low calorie triglyceride compositions of the present invention provides a highly desirable food composition. In addition, the low calorie triglyceride compositions can be blended with other low calorie fats, fat replacers or fat mimetics.
Thus, the acylated glyceride compositions of the present invention can be used in a variety of applications. Of particular interest in the present invention is the use of the low calorie triglyceride compositions in various food applications. Of most particular interest is the use in low calorie food applications.
Thus, the acylated glyceride compositions of the present invention find use in the preparation of foods, food products, processed foods, food ingredients, food additive compositions, or dietary supplements that contain oils and/or fats. Examples of such uses include but are not limited to margarines, butters, shortenings, dressings, spreads, frying oils, mayonnaises, and vitamin/mineral supplements. Additional examples include, but are not limited to toppings, dairy products such as cheese and processed cheese, processed meat and meat mimetics, pastas, cereals, sauces, desserts including frozen and shelf stable desserts, dips, chips, baked goods, pastries, cookies, snack bars, confections, chocolates, beverages, unextracted seed, and unextracted seed that has been ground, cracked, milled, rolled, extruded, pelleted, defatted, dehydrated, or otherwise processed, but which still contains the oils, etc., disclosed herein.